GB604180A - Improvements in electric rectifying circuits employing indirectly heated tubes - Google Patents

Abstract

604,180. Rectifying. PHILIPS LAMPS, Ltd. Aug. 1, 1946, No. 22918. Convention date, Feb. 14, 1940. [Class 38 (ii)] In supplying a load such as the valve filaments K1 ... K4 of a radio receiver from A.C. supply mains 1, 2 through a rectifying valve G having an indirectly heated cathode, switch means t 1 , t 2 are provided whereby the cathodeheater is first connected across the mains, through resistance R 1 , and later when the cathode has reached operating temperature, is connected in series with the load. The switch means may comprise a thermal relay, the heating winding T of which is connected in one of the main supply leads. Alternatively, an electro-magnetic relay, the exciting winding of which is in series with the discharge path of the rectifier, may be used. The rectifier may also supply anode and screen grid voltages to the radio valves at terminals 3, 4 through a smoothing network C 1 , C 2 , L. As an alternative supply, high tension and low tension batteries may be connected at terminals 3, 4 and 5, 6 and the switch-means may be arranged to switch over from batteries to mains when the cathode of the mains rectifier valve reaches operating temperature, Fig. 2 (not shown). The arrangement may be also applied to battery charging.